delete data of csv file

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SINDU GOKULAPATI
SINDU GOKULAPATI 2021-3-24
编辑： SINDU GOKULAPATI 2021-5-16
i have created a code such that data is appended to csv file every time the loop runs
but when i run the program again the new data is added with the old one
but i want to clear out the data in then csvfile before hand
what command do i use
delete('xyz.csv') deletes the whole file
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Merve Buyukbas
Merve Buyukbas 2021-3-24
But you shouldn't count on the main directory and instead use full paths everywhere in your script. This way the data can be located anywhere independently on where the code is.
SINDU GOKULAPATI
SINDU GOKULAPATI 2021-3-24
im sorry i dont know if im not explaning properly
i have a csv file with all numbers it self ,let that be just 3 cells in my csv with data 1,2,3
if i open csv file i can see those three cells only
now using code in matlab i want to erase those
so now when i open that csv file it should be empty
there is no .txt or sring data
hope my question is conveys right

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Walter Roberson
Walter Roberson 2021-3-24
fclose(fopen('xyz.csv', 'w'));
When you open a file for writing with 'w' access, the existing content is discarded.
Note: the POSIX standard library specifies truncate() and ftruncate() functions that would be a closer match. However, MATLAB does not implement either of those.
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Walter Roberson
Walter Roberson 2021-5-12
csvread() calls dlmread() with delimiter ','
You are writing to a file that is not necesarily in the same place as you are reading from, as your current directory is not necessarily D:\sem6\PROJECT
SINDU GOKULAPATI
SINDU GOKULAPATI 2021-5-16
编辑：SINDU GOKULAPATI 2021-5-16
hey walter i specified the directory but still giving error,
for context
for i=1:n
for j=1:n
angle = transpose(rnorm{i})*rnorm{j};
if angle > cosd(20) && angle <= cosd(0)
matrix = [i,j,angle];
dlmwrite('D:\sem6\PROJECT\on.csv',(matrix),'-append')
end
end
k=0;
s=dlmread('D:\sem6\PROJECT\on.csv',',',1,2);
store= histcounts(s); //need histogram for each point wrt to angle subjected to other points
fclose(fopen('D:\sem6\PROJECT\on.csv','w')); //to rewite for every 'i'
end
ps: i have attachec csv file with 50 rnorm value (intended output is 50 histograms)

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